linux-kernel - Re: [PATCH] kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH

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Message-ID: <ZWfoOLEnS+TnikpA@MiWiFi-R3L-srv>
Date:   Thu, 30 Nov 2023 09:41:12 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Ignat Korchagin <ignat@...udflare.com>
Cc:     linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, akpm@...ux-foundation.org,
        eric_devolder@...oo.com, agordeev@...ux.ibm.com,
        kernel-team@...udflare.com, stable@...r.kernel.org
Subject: Re: [PATCH] kexec: drop dependency on ARCH_SUPPORTS_KEXEC from
 CRASH_DUMP

On 11/29/23 at 10:04pm, Ignat Korchagin wrote:
> In commit f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for
> CRASH_DUMP") we tried to fix a config regression, where CONFIG_CRASH_DUMP
> required CONFIG_KEXEC.
> 
> However, it was not enough at least for arm64 platforms. While further testing
> the patch with our arm64 config I noticed that CONFIG_CRASH_DUMP is unavailable
> in menuconfig. This is because CONFIG_CRASH_DUMP still depends on the new
> CONFIG_ARCH_SUPPORTS_KEXEC introduced in commit 91506f7e5d21 ("arm64/kexec:
> refactor for kernel/Kconfig.kexec") and on arm64 CONFIG_ARCH_SUPPORTS_KEXEC
> requires CONFIG_PM_SLEEP_SMP=y, which in turn requires either CONFIG_SUSPEND=y
> or CONFIG_HIBERNATION=y neither of which are set in our config.
> 
> Given that we already established that CONFIG_KEXEC (which is a switch for kexec
> system call itself) is not required for CONFIG_CRASH_DUMP drop
> CONFIG_ARCH_SUPPORTS_KEXEC dependency as well. The arm64 kernel builds just fine
> with CONFIG_CRASH_DUMP=y and with both CONFIG_KEXEC=n and CONFIG_KEXEC_FILE=n
> after f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP")
> and this patch are applied given that the necessary shared bits are included via
> CONFIG_KEXEC_CORE dependency.
> 
> Fixes: 91506f7e5d21 ("arm64/kexec: refactor for kernel/Kconfig.kexec")
> Cc: stable@...r.kernel.org # 6.6+: f8ff234: kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP
> Cc: stable@...r.kernel.org # 6.6+
> Signed-off-by: Ignat Korchagin <ignat@...udflare.com>
> ---
>  kernel/Kconfig.kexec | 1 -
>  1 file changed, 1 deletion(-)

This is a good catch, thanks.

Acked-by: Baoquan He <bhe@...hat.com>

> 
> diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
> index fc38f1ae3a30..946dffa048b7 100644
> --- a/kernel/Kconfig.kexec
> +++ b/kernel/Kconfig.kexec
> @@ -96,7 +96,6 @@ config KEXEC_JUMP
>  config CRASH_DUMP
>  	bool "kernel crash dumps"
>  	depends on ARCH_SUPPORTS_CRASH_DUMP
> -	depends on ARCH_SUPPORTS_KEXEC
>  	select CRASH_CORE
>  	select KEXEC_CORE
>  	help
> -- 
> 2.39.2
>